Manufacturing fibreboard by the existing method involves using the so-called wet method whereby the fibres are suspended in water which is then poured out on a screen so forming a sheet which is then given its final form in a hot press which also removes excess water. One disadvantage with this formation method is that when the fibres in the water suspension are spread out over the screen, a process which occurs relatively rapidly, the fibres end up lying along the direction of the path of the machine which results in a board in which the fibres are relatively oriented substantially in one direction. This results in variations in strength lengthwise and crosswise of the sheet and the board, which is disadvantageous.
In the production of boards according to the dry method, the sheet or mat is formed by suspending fine fibre particles in the air and depositing them on an underlying moving screen without any intermediate suspension in water. The so-called dry, half-dry or high-concentration forming methods result in a fibreboard in which the fibres are randomly oriented so that the sheet and the final board are equally as strong in all directions. However, one disadvantage with this method is that a bonding agent must be used to bind the fibres together, and this lengthens and complicates the process.